After racking the beer out of the primary, I leave a very tiny bit (think just barely enough to cover the compacted yeast cake) of beer on the yeast. Vigorously swirl the cake up into suspension, let sit for a few minutes for the major trub and hop debris to settle out, then carefully decant (after sanitizing the carboy opening) into a 500 mL (or so) mason jar filling it to the rim. Quickly put a sanitized lid on top but don't screw it down all the way tight. Let it sit in the fridge as cold as possible (mine are about 35F) to settle out. I tighten the lid down a little at at time over the next day or so just to be sure there is no more outgassing from the yeast/beer and periodically check them to relieve pressure if necessary. Either repitch the next day or two (best) or within a week if need be.